Due to their superior stability and lower price point, duplex stainless steels are becoming increasingly common in the contemporary industry. Duplex stainless steel basically is a whole family of stainless steel, which have been termed as duplex grade due to the fact that their metallurgical structure comprises of two distinct phases – ferrite, and austenite. Ferrite is a body centered cubic lattice, while austenite is a face-centered cubic lattice, and both of them can be found in duplex stainless steels in approximately an equal proportion.

In comparison to the typical austenitic stainless steels, the premium duplex stainless steel sheets are known to provide superior corrosion resistance, especially when it comes to chloride pitting corrosion and chloride stress corrosion. The commendable uniform and local corrosion resistant capacity of duplex stainless steel can be largely attributed to their high molybdenum, chromium and nitrogen content.

Duplex Stainless Steel has a distinct duplex microstructure that plays a major role in boosting their strength and providing them high resistance capacity against stress corrosion cracking. They, essentially, are stronger and more durable than the standard type 304 or 316 austenitic stainless steels. Duplex stainless steel is known to have an impressive weldability as well.

Duplex vs Super Duplex Cost

Duplex Steel Price Per Kg

Duplex Stainless Steel PriceOriginPrice in INR
(per kg)
Price in USD
(per kg)
Price in Euro
(per kg)
Duplex Steel Price in IndiaIndianRs 260/-$3.69€3.19
Duplex Steel Price in MalaysiaMalaysiaRs 270/-$3.83€3.31
Duplex Stainless Steel Price in SingaporeSingaporeRs 280/-$3.97€3.43
Duplex Stainless Steel Price in JapanJapaneseRs 280/-$3.97€3.43
Duplex Stainless Steel Material Price in UK / EuropeEuropeanRs 300/-$4.25€3.68
Duplex Stainless Steel Price in USAUSARs 350/-$4.96€4.29

Super Duplex Stainless Steel Price Per Kg

Super Duplex Stainless Steel PriceOriginPrice in INR
(per kg)
Price in USD
(per kg)
Price in Euro
(per kg)
Super Duplex Stainless Steel Price in IndiaIndianRs 280/-$3.97€3.43
Super Duplex Steel Price in MalaysiaMalaysiaRs 290/-$4.11€3.55
Super Duplex Price Per Kg in SingaporeSingaporeRs 300/-$4.25€3.68
Super Duplex Steel Price in JapanJapaneseRs 320/-$4.54€3.92
Super Duplex Stainless Steel Material Price in UK / EuropeEuropeanRs 340/-$4.82€4.17
Super Duplex Steel Price in USAUSARs 380/-$5.39€4.66

Key features of the Duplex Stainless Steels

  • Strength: The duplex stainless steel is known to have about doubled the strength than that of ferrite or austenitic stainless steels.
  • Ductility: The ductility feature of duplex stainless steel is considerably better than that of ferrite grade steel.
  • Corrosion resistance:  The composition of the stainless steel sheets is the key factor on which its corrosion resistance depends on. The duplex stainless steel grades are known to have quite high corrosion resistance capacity.
  • Stress corrosion cracking resistance: The stress corrosion cracking (SCC) resistance of duplex stainless steels is quite good. This is a property that the duplex stainless steel inherits from its ferritic side. SCC, however, can prove to be a problem for standard austenitics in certain scenarios, like elevated temperature and humidity.
  • Cost: The molybdenum and nickel content in duplex stainless steel is lower in comparison to its austenitic counterparts that have similar corrosion resistant properties. The price of duplex stainless steels hence tends to be lower due to its lesser alloying content. Reducing the section thickness of duplex stainless steel additionally can often be possible, owing to its augmented yield strength in comparison to the austenitic variants. The combination might result in considerable weight and cost savings as opposed to a solution of austenitic stainless steel.
  • Heat Resistance: Duplex stainless steel is known to have a high chromium content that protects the material against corrosion, while causing embrittlement at temperatures more than 300°C. The duplex stainless steel typically has a superior ductility than the martensitic and ferritic grades, and can be used down to around -50°C quite readily.
  • Weldability: The weldability factor of duplex stainless steel is quite good, and almost all the standard welding processes can be used for it. While duplex stainless steel cannot be welded as easily as the typical austenitic grades, the low thermal expansion of this material significantly reduces residual stresses and distortion subsequent to welding. 2209 would be the ideal filler material for 2205 stainless steel.

In addition to the above-mentioned features, duplex stainless steel also has a certain magnetic property that is not common in the typical austenitic stainless steel.

The fabrication of duplex stainless steel sheet should only be done by certain dedicated tools. Prior to use, all the relevant tools and work surfaces should be cleaned in a thorough fashion. It is crucial to take these precautionary measures in order to avoid the contamination of duplex stainless steel, which can discolor the fabricated product surface.

While heat treatment cannot be used in order to harden duplex stainless steel, they can be work hardened. Annealing or solution treatment on duplex stainless steel can be done through rapid cooling subsequent to heating about 1100°C.

View Super Duplex Stainless Steel Composition. Here are some typical composition of Hyper Duplex Stainless Steel, 22 Cr Duplex Stainless Steel, 1.4462 Duplex Stainless Steel and Lean Duplex Stainless Steel:

Grade EN No/UNSTypeApprox Composition 
CrNiMoNMnWCu
2101 LDX1.4162/ 
S32101
Lean21.5 1.50.30.225
DX22021.4062/ S32202Lean232.50.30.21.5
RDN 9031.4482/ 
S32001
Lean201.80.2 0.114.2
23041.4362/ 
S32304
 Lean234.8 0.3 0.10
22051.4462/ 
S31803/ 
S32205
Standard 225.73.10.17
25071.4410/ 
S32750
Super25740.27
Zeron 1001.4501/ 
S32760
Super25 73.20.250.70.7
Ferrinox 
255/ 
Uranus 2507Cu
1.4507/ 
S32520/ 
S32550
Super256.53.50.251.5

Duplex Stainless Steel Equivalent

GradeEN No / UNSType
2101 LDX 1.4162/ S32101Duplex
23041.4362/ S32304Duplex
DX22021.4062/ S32202Duplex
Duplex 2205 1.4462/ S31803/ S32205Duplex
Zeron 100 1.4501/ S32760Duplex
Ferrinox 255/ 
Uranus 2507Cu
1.4507/ S32520/ S32550Duplex
Super Duplex 25071.4410/ S32750Duplex
6% Mo1.4547/ S31254Austenitic

Machinability of Duplex stainless steel

Even though duplex stainless steel is machinable, their high strength and sturdiness at times can make machining a bit difficult. Here are a few pointers that can be followed for the purpose of augmenting the machining capacity of duplex stainless steel:

  • As dull edges can result in extra work hardening, cutting edges should be kept as sharp as possible
  • While the cuts must be light, it should also be deep enough to prevent the instance of work hardening by riding on the surface of the relevant material
  • To make sure that swarf remains clear of the work, chip breakers must be used
  • The austenitic alloys have a low thermal conductivity that ultimately results in heat concentrating at the cutting edges. This invariably means that lubricants and coolants are highly necessary and should be used in expansive quantities. 

Duplex Steel Grades

Duplex stainless steel is famed for being the most widely used grade of stainless steel.  These variants of stainless steel are characterized by their high yield strength and impressive corrosion resistant capacity, and tend to be quite popular demand due to their affordability and price stability.

There are several grades of duplex stainless steel found in the market today. Here are a few of them:

  • S32520
  • S32001
  • S31803
  • S32205
  • S32304
  • 4404
  • 2304
  • 4501
  • 4521
  • LDX 2101
  • 254 SMO
  • 2507
  • 4301

As the Duplex stainless steels are magnetic, they can be differentiated quite easily from the typical austenitic grades.

Duplex stainless steels can very easily be differentiated from other austenitic grades of stainless steel, as they are magnetic.

Grade EN No/UNSType
22051.4462/ S31803/ S32205Standard

Lean duplex stainless steel grades

Lean duplex stainless steel grade EN No/ UNSType
2101 LDX1.4162/ S32101Lean
DX22021.4062/ S32202Lean
RDN 9031.4482/ S32001Lean
23041.4362/ S32304Lean

The 2304 duplex steel grade is one of the most commonly used variants of duplex stainless steels, and is often referred to as lean duplex grade as well. This grade of duplex steel is known to have heightened mechanical strength, fine weldability, good thermal conductivity, impressive machinability and high resistance to stress corrosion splitting.

The 2507 stainless steel super duplex grade additionally is known to have elevated levels of nickel, molybdenum, and chromium, and therefore is able to provide excellent resistance to general and pitting corrosion.

In addition to having the typical advantageous features of duplex stainless steels, the LDX2101 Stainless Steel boasts of incredible durability and strength.

 

Super Duplex Steel Grades

There are seven major grades of super duplex steel. These grades include S32750, S32760, S31260, S32550, S32950, S31200 and S32900.  The super duplex stainless steel is extremely sturdy, tough and hard-wearing, and have quite high corrosion resistant. The term “Super-Duplex” was first used sometime in the 1980s in order to refer to a high-performance and highly alloyed duplex steel that featured a great pitting resistance. Owing to the high levels of chromium content found in Super Duplex Steel Grades, it is able to provide high resistance to caustic solutions, acid chlorides, and acids. This factor makes the super duplex stainless steel ideal for use in the environments of pulp and paper industries, as well as chemical/petrochemical domain. They tend to often replace 300 series stainless steel, nickel-based alloys, and high nickel super austenitic steels. The super duplex stainless steels are also commonly used in the marine and chemical industries.

The general composition of super duplex stainless steels is known to have high nickel, molybdenum and chromium levels, as well as a bit of addition of nitrogen. All these components go on to enhance the yield strength of the super duplex steel grades. The addition of nitrogen made to the super duplex stainless steels aids in promoting hardening with the help of solid solution mechanism. This factor aids in augmenting the ultimate strength value and yield strength of the material without impairing its general toughness in any manner. The two-phase microstructure of the super duplex stainless steels provides high assurance of superior resistance to stress and pitting corrosion cracking in comparison to any conventional stainless steel.

Super Duplex Grade EN No/UNSType
25071.4410/ S32750Super Duplex
Zeron 1001.4501/ S32760Super Duplex
Ferrinox 255/ Uranus 2507Cu1.4507/ S32520/ S32550Super Duplex

The Duplex Stainless Steel applications

There are multiple industries where Duplex Stainless Steel is used quite popularly. Some of those industries include:

  • Biomass
  • Mining
  • LNG (Liquefied Natural Gas)
  • Utilities
  • Nuclear Power
  • Oil and Gas
  • Pharmaceutical
  • Geothermal
  • Sea Water
  • Water Desalination
  • Solar Power
  • Petrochemical

Here is more on the uses of duplex stainless steels in the modern industries:

  • Structural and mechanical components
  • Pies and heat exchangers in desalination plants
  • Power industry FGD systems,
  • Pipes in process industries that handle solutions that contain chlorides
  • Places where high corrosion fatigue strength can be made use of, such as fans, rotors, utility, and industrial systems, press rolls and shafts
  • Consumables for chemical tankers
  • High resistant and high strength wiring

Duplex stainless steel pipes and fittings, tubes and heat exchangers are used for handling and production of oil and gas.  People can also find duplex stainless steel fasteners used in many demanding environments where superior mechanical and corrosion resistance properties are required. 

The Duplex Stainless Steel Market

The market of duplex stainless is quite expansive, and there is an extremely high demand for this material across the world owing to its incredible properties. The duplex stainless steel is known to have metallurgy that is a lot complex in comparison to that of austenitic steels or ferritic steels.  As per reports, the duplex stainless steel market is expected to reach USD 3.40 billion by 2021.

Pitting resistance equivalent numbers (PREN) are a theoretical way of comparing the pitting corrosion resistance of various types of stainless steels, based on their chemical compositions.

GradeEN NoTypeTypical PREN number
2101 LDX / S321011.4162Duplex26
2304 / S323041.4362Duplex26
DX2202 / S322021.4062Duplex27 
Duplex 2205 / S31803/ S322051.4462Duplex35
Zeron 100 / S327601.4501Duplex41
Ferrinox 255/ Uranus 2507Cu / S32520/ S325501.4507Duplex41
Super Duplex 2507 / S327501.4410Duplex43
6% Mo/ S312541.4547Austenitic44

Duplex Stainless Steel Inventory

Location wise estimated delivery time for Austenitic Ferritic Duplex & Super Duplex Stainless Steel

CountryDaysCountryDays
Vietnam20Albania20
UAE15Thailand20
Nigeria40Ethiopia40
Turkey30Tanzania30
Bahrain15Kenya40
Libya40Syria40
Zambia40Egypt40
Italy40India7
Saudi Arabia15Qatar15
Namibia40Indonesia20
South Africa40Australia40
Uganda40Angola40
Kazakhstan20Algeria20

Hyper Duplex Stainless Steel suppliers

We offer high quality, lower cost but the best service. As a result to that our export account today is in over 45 countries some of them are United States, United Arab Emirates, Canada, Pakistan, Spain, France, United Kingdom, Indonesia, Iran, Kuwait, Mexico, Malaysia, Nigeria, Singapore, Saudi Arabia, Netherlands, Brazil, Colombia, Egypt, Iraq, Sri Lanka, Russia, Vietnam, South Africa,, Nigeria, Turkey, Bangladesh, Italy, Japan, Thailand, Hong Kong, Switzerland, New Zealand We welcome your inquiries.